Upright silos are commonly used to store silage for livestock. The silage is generally removed from the silo by an uloading system positioned at the top or bottom of the silo. This invention is for use with a silo having an unloader to remove the silage from the top of the silo and discharge it through the wall of the silo into the discharge chute.
Silos, which are unloaded from the top, generally have a vertical row of doors which extend from the bottom of the silo to the top. These doors close a passage from the inside of the silo to a vertical silo dishcharge chute on the outside of the silo wall. A silo unloader inside the silo removes silage from the top of the silage and conveys into the vertical silo discharge chute. The silage falls down the discharge chute and into a hopper for a conveyor system for distribution to livestock. As the silage is removed from the silo, it is necessary at various points in time for the operator to climb up the inside of the silo discharge chute to open the doors through which the silage is conveyed and to reposition the unloaders. At other times the unloader may require service, and access to the silo is obtained through the discharge chute.
U.S. Pat. No. 3,169,620, which issued to Patz, Feb. 16, 1965, disclosed a swingable silo spout which may be moved to the side to allow access to the interior of the silo discharge chute. Therefore, if the farmer must enter the chute to service the silo unloader or to open the next door of the discharge chute, the silo spout, which is positioned below the discharge chute, may be swung to one side allowing the farmer entry into the chute. As can be seen in the drawings of the reference, the spout is secured to the lower rungs of the silo ladder, thereby simplifying installation of the unit. This particular structure is made of sheet metal and it is not designed to provide a seal with the lower edge of the discharge chute. As such, there is a gap between the lower edge of the discharge chute 2 and the upper edge of the spout which will allow some of the discharged silage to escape. This is not desirable; however due to the different types of silo built and the different types of discharge chutes which can be secured to them, it has proven difficult to provide one structure which can universally be applied to all silos. Therefore, generally the prior art silo chute have compromised on the design features in order to provide a system which can be applied to most silos.
U.S. Pat. No. 3,699,732, which issued to Janssen et al., Oct. 24, 1972, discloses a collapsible liner for a silo chute which overcomes the leakage problem discussed in Patz's structure. According to this patent, a collapsible discharge chute liner is possible which keeps the discharge chute clean and relatively free of dust, such that the operator can climb up into the discharge chute and adjust either the liner or the unloader without being in direct contact with silage stuck in the chute. This collapsible liner keeps the discharge chute relatively clean; however, the farmer must climb up the discharge chute and reposition the funnel member 28 when the silage reaches a certain level.
U.S. Pat. No. 3,124,229, which issued to Rutten, Mar. 10, 1964, disclosed an adjustable hopper arrangement for the discharge chute of a silo, where the hopper is adjustable to more closely fit the size of the discharge chute to which the device is being secured. Again the hopper is pivoted to the silo chute and may be swung outwardly to allow access to the discharge chute. This device is made of a sheet metal material with a plurality of rivets or bolts securing it together. As can be seen in FIGS. 2, the hopper does not provide a seal with the base of the discharge chute and, therefore, some leakage of the unloaded silage may result. These patents only have one discharge position and height.
The present invention provides a simple, effective means for controlling the discharge of silage from the discharge chute of a silo in a manner which reduces leakage and minimizes waste of silage. The system is capable of operating under a variety of different conditions, as various types of silage will be used and the moisture content thereof can change substantially. The system reduces corrosion, while still providing access to the discharge chute of the silo. Convenience for the farmer is important and, therefore, the system is simple and rugged. Because of the varying type and construction of silos and the various different types of discharge chutes, the system is flexible so that it can function with the individual combinations of discharge chutes and silos found in the field. The system also allows the discharge of silage to be directed as it may be necessary to load the silage onto a conveyor or merely to load directly into a feed cart. Individual users may use both methods. The present invention provides a simple system with improved operating characteristics over those of the prior art.